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Need for nitrate level and testing in cooling water system

Nitrites added are added to avoid
  • corrosion attack 
  • sludge formation
  • scale deposits

Sodium nitrite or Sodium Borate

  • It is used because they are safe for handling , non toxic , not dangerous if over dosed and contain a pH buffer to provide protection against acidic corrosion
  • They form a thin passive oxide  surface layer on the metal  
  • Sodium Borate is used when te material to be protected involves zinc or soft solder material.

**Oher chemical like 
Chromates are not used since it is highly toxic and unsafe during handling and disposal.
Soluble Emulsion oil are not used due to bacterial contamination , disposal problems and no control over film thickness

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